弱公钥模型集下的零知识论证系统

根据近年来弱公钥模型集下的零知识系统的研究成果,对其发展历程和特性设置进行阐释和剖析,探讨该模型集下最优轮数的零知识协议的构造方法,提出通用的4轮模式和3轮模式,以及协议的（并发）健壮性和（可重置）零知识的证明技术和问题,并总结弱公钥模型集下零知识系统的研究将来可能发展的导向。     

A theorem on atomicity in distributed algorithms

Reasoning about a distributed algorithm is simplified if we can ignore the time needed to send and deliver messages and can instead pretend that a process sends a collection of messages as a single atomic action, with the messages delivered instantaneously as part of the action. A theorem is derived that proves the validity of such reasoning for a large class of algorithms. It generalizes and corrects a well-known folk theorem about when an operation in a multiprocess program can be considered atomic.List of notations A The set of program actions - A The algorithm under consideration - A The reduced version of algorithmA - A The action obtained by executing the operationA as an atomic action - C The set of state components - d[i] A variable of the Distance-Finding Algorithm - L An operation ofA, as in C2 - The operation obtained by adding toL the actions that deliver messages sent byL - N _p(S) The set of possible next actions of processp from states - P The correctness property - R An operation ofA, as in C2 - S The set of states - S ₀ The set of initial states - S _c The range of values of state componentc - X An action ofA, as in C2 - Usually denotes an execution ofA - The execution ofA that corresponds to an execution ofA When snow conditions are poor,Dr. L. Lamport works at Digital Equipment Corporation's Systems Research Center. As an undergraduate, he took a course in atomic physics.     

High performance computing for the level-set reconstruction algorithm

A parallelized version of the level-set algorithm based on the MPI technique is presented. TM-polarized plane waves are used to illuminate two-dimensional perfect electric conducting targets. A variety of performance measures such as the efficiency, the load balance, the weak scaling, and the communication/computation times are discussed. For electromagnetic inverse scattering problems, retrieving the target’s arbitrary shape and location in real time is considered as a main goal, even as a trade-off with algorithm efficiency. For the three cases considered here, a maximum speedup of 53X-84X is achieved when using 256 processors. However, the overall efficiency of the parallelized level-set algorithm is 21%–33% when using 256 processors and 26%–52% when using 128 processors. The effects of the bottlenecks of the level-set algorithm on the algorithm efficiency are discussed.     

倾斜长壁综采工作面分合式快速过断层技术

林东冒沙煤矿4842工作面回采遇断层时,须将工作面设备及支架搬到下段,需重新开切眼,采用中间分合式撤面安装工艺,仅用14 d时间就回撤安装完毕,工作面通过断层.     

Towards a natural language semantics without functors and operands

The paper sets out to offer an alternative to the function/argument approach to the most essential aspects of natural language meanings. That is, we question the assumption that semantic completeness (of, e.g., propositions) or incompleteness (of, e.g., predicates) exactly replicate the corresponding grammatical concepts (of, e.g., sentences and verbs, respectively). We argue that even if one gives up this assumption, it is still possible to keep the compositionality of the semantic interpretation of simple predicate/argument structures. In our opinion, compositionality presupposes that we are able to compare arbitrary meanings in term of information content. This is why our proposal relies on an ‘intrinsically’ type free algebraic semantic theory. The basic entities in our models are neither individuals, nor eventualities, nor their properties, but ‘pieces of evidence’ for believing in the ‘truth’ or ‘existence’ or ‘identity’ of any kind of phenomenon. Our formal language contains a single binary non-associative constructor used for creating structured complex terms representing arbitrary phenomena. We give a finite Hilbert-style axiomatisation and a decision algorithm for the entailment problem of the suggested system.     

Using fuzzy self-organising maps for safety critical systems

This paper defines a type of constrained artificial neural network (ANN) that enables analytical certification arguments whilst retaining valuable performance characteristics. Previous work has defined a safety lifecycle for ANNs without detailing a specific neural model. Building on this previous work, the underpinning of the devised model is based upon an existing neuro-fuzzy system called the fuzzy self-organising map (FSOM). The FSOM is type of ‘hybrid’ ANN which allows behaviour to be described qualitatively and quantitatively using meaningful expressions. Safety of the FSOM is argued through adherence to safety requirements—derived from hazard analysis and expressed using safety constraints. The approach enables the construction of compelling (product-based) arguments for mitigation of potential failure modes associated with the FSOM. The constrained FSOM has been termed a ‘safety critical artificial neural network’ (SCANN). The SCANN can be used for non-linear function approximation and allows certified learning and generalisation for high criticality roles. A discussion of benefits for real-world applications is also presented.     

Interconnection Network Simulation Using Traces of MPI Applications

This paper addresses the utilization of traces taken from MPI applications to do simulation-based performance studies of parallel computing systems. Different mechanisms to capture traces are discussed, pointing out important limitations of some of them. One of these limitations is the invisibility of message interchanges in collective operations, which is circumvented modifying a trace-capturing library. During a simulation, trace records must be simulated in causal order, to fully comply with application semantics. Alternatives to follow this order, and the risks of not following it, are presented and discussed. The techniques introduced in this paper have been implemented in an in-house developed simulation environment, which is used in two example studies to show its usefulness: an evaluation of alternatives for interconnection network design, and a performance prediction study in which traces from one machine are used to estimate the execution times of applications running in a different machine.     

Accelerating Scientific Discovery Through Computation and Visualization

The rate of scientific discovery can be accelerated through computation and visualization. This acceleration results from the synergy of expertise, computing tools, and hardware for enabling high-performance computation, information science, and visualization that is provided by a team of computation and visualization scientists collaborating in a peer-to-peer effort with the research scientists.In the context of this discussion, high performance refers to capabilities beyond the current state of the art in desktop computing. To be effective in this arena, a team comprising a critical mass of talent, parallel computing techniques, visualization algorithms, advanced visualization hardware, and a recurring investment is required to stay beyond the desktop capabilities.This article describes, through examples, how the Scientific Applications and Visualization Group (SAVG) at NIST has utilized high performance parallel computing and visualization to accelerate condensate modeling, (2) fluid flow in porous materials and in other complex geometries, (3) flows in suspensions, (4) x-ray absorption, (5) dielectric breakdown modeling, and (6) dendritic growth in alloys.     

油井深抽过泵产液剖面测试技术

为准确找出油井的出水层段，研究了深抽过泵产液剖面测试技术。该工艺技术在油井检泵作业施工期间．进行，在井下2000m以内套管上悬挂空心测试抽汲泵，通过油管驱动深抽产液，测试仪器从油管下入并过泵柱塞到达测试层段，进行不停抽测试，得到产液剖面资料，判断出主产水层，进行有针对性的卡堵水作业。适用于斜井、稠油井、螺杆泵井、电潜泵井、水力泵井等无法进行环空测试的油井。在华北油田成功实施了50余井次，为油田开发方案的判定提供了较为准确的资料。